When a table is loaded on startup during a vnodes-to-tablets migration
(forward or rollback), the `table_populator` runs a resharding
compaction.
Set the migration virtual task as parent of the resharding task. This
enables users to easily find all node-local resharding tasks related to
a particular migration.
Make `migration_virtual_task::make_task_id()` public so that the
`distributed_loader` can compute the migration's task ID.
Signed-off-by: Nikos Dragazis <nikolaos.dragazis@scylladb.com>
295e434781